Optical device

Abstract

An optical device that includes first and second members that is rotatable relative to the first member is provided that includes a coupling unit that is provided for the second member; and a position detecting unit that has a detecting part disposed at the first member and a detected part disposed at the second member, and is configured to detect a position of the second member relative to the first member. When viewed from a direction along a rotation central axis of the second member, an angle between a first axis and a second axis at a position within a rotational range of the second member is 90 degrees. The first axis is an axis that is perpendicular to the rotation central axis and passes through the detecting part and the second axis is an axis that is perpendicular to the rotation central axis and passes through the coupling unit.

What is claimed is: 
     
       1. An optical device comprising:
 a first member; 
 a second member that is rotatable relative to the first member around a rotation central axis; 
 a coupling unit that is disposed at the second member; and 
 a position detecting unit that has a detecting part disposed at the first member and a detected part disposed at the second member, and is configured to detect a position of the second member relative to the first member, 
 wherein, when viewed from a direction of the rotation central axis, an angle between a first axis and a second axis is 90 degrees at a predetermined position within a rotational range of the second member, and 
 wherein the first axis is an axis that is perpendicular to the rotation central axis and passes through the detecting part and the second axis is an axis that is perpendicular to the rotation central axis and passes through the coupling unit. 
 
     
     
       2. The optical device according to  claim 1 , wherein the detecting part and the coupling unit are in a positional relationship in which the first axis and the second axis form a right angle, and
 wherein the position of the second member in a direction centered on the rotation central axis is a central position within the rotational range. 
 
     
     
       3. The optical device according to  claim 1 , wherein the coupling unit includes first and second coupling units disposed at the second member. 
     
     
       4. The optical device according to  claim 3 , further comprising:
 an operating member that is engaged with the first coupling unit; and 
 a rotary member that is engaged with the second coupling unit and configured to rotate in conjunction with the rotation of the second member by the operating member. 
 
     
     
       5. The optical device according to  claim 1 , further comprising
 a first position detecting unit that optically detects a position of the second member relative to the first member is set as a first position detecting unit, 
 wherein the optical device further includes a second position detecting unit that detects the position of the second member relative to the first member using a change in resistance value. 
 
     
     
       6. The optical device according to  claim 5 , wherein the second position detecting unit has a variable resistance sensor mounted on the first member, and
 wherein, when viewed from the direction along the rotation central axis, the variable resistance sensor is symmetrically disposed with respect to the detecting part constituting the first position detecting unit with the rotation central axis interposed therebetween.